ASAHIKAWA, HOKKAIDO – A Hokkaido court convicted a man Thursday of possessing stimulant drugs, but ruled some of the evidence gathered by police using GPS data without a warrant was inadmissible.

The Asahikawa District Court sentenced Masayuki Tanikawa, 46, a former gangster, to six years in prison and fined him ¥1.5 million ($13,600) for possessing 61 grams of stimulant drugs.

Tanikawa was arrested in the parking lot of a hospital in Asahikawa on May 2017 and police deemed the drugs were for commercial purposes and not personal use.

Presiding Judge Hidehiko Sato said the crime was “sufficiently provable” through the evidence obtained through interrogation.

Tanikawa’s defense claimed during the trial that data from a GPS device that the police had attached intermittently to the defendant’s car since 2013 and footage from a surveillance camera set up by the police to monitor the garage could not stand as evidence because it had been obtained illegally.

Prosecutors argued that Tanikawa was charged based on evidence that the police collected through other means and was not closely linked to the GPS data. They had sought a seven-year prison term and a fine of ¥1.5 million.

As for the surveillance camera, the prosecutors asserted its legitimacy, saying that police were monitoring a parking lot adjacent to a public road and were not invading a private area.

On the matter, the court sided with the prosecution team.

In March 2017, the Supreme Court ruled against warrantless GPS data collection in investigations, saying it violates privacy, and said even investigations making use of GPS devices with a warrant were questionable.

In Tanikawa’s trial, prosecutors also said that the investigators had used the GPS device before the top court’s ruling, and they had thought that they were able to conduct such an investigation without a warrant at that time.

Following the ruling by the Supreme Court, the National Police Agency ordered all prefectural police to refrain from using GPS devices in investigations.